linux-kernel - [tip:smp/hotplug] KVM/x86: Remove superfluous SMP function call

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Message-ID: <tip-162e52a117af5d9c5dfc62b7c2ee90b3e91a7b32@git.kernel.org>
Date:	Tue, 19 Jul 2016 00:13:37 -0700
From:	tip-bot for Anna-Maria Gleixner <tipbot@...or.com>
To:	linux-tip-commits@...r.kernel.org
Cc:	pbonzini@...hat.com, mingo@...nel.org,
	torvalds@...ux-foundation.org, hpa@...or.com,
	anna-maria@...utronix.de, peterz@...radead.org,
	linux-kernel@...r.kernel.org, tglx@...utronix.de,
	rkrcmar@...hat.com
Subject: [tip:smp/hotplug] KVM/x86: Remove superfluous SMP function call

Commit-ID:  162e52a117af5d9c5dfc62b7c2ee90b3e91a7b32
Gitweb:     http://git.kernel.org/tip/162e52a117af5d9c5dfc62b7c2ee90b3e91a7b32
Author:     Anna-Maria Gleixner <anna-maria@...utronix.de>
AuthorDate: Wed, 13 Jul 2016 17:16:32 +0000
Committer:  Ingo Molnar <mingo@...nel.org>
CommitDate: Fri, 15 Jul 2016 10:40:21 +0200

KVM/x86: Remove superfluous SMP function call

Since the following commit:

  1cf4f629d9d2 ("cpu/hotplug: Move online calls to hotplugged cpu")

... the CPU_ONLINE and CPU_DOWN_PREPARE notifiers are always run on the hot
plugged CPU, and as of commit:

  3b9d6da67e11 ("cpu/hotplug: Fix rollback during error-out in __cpu_disable()")

the CPU_DOWN_FAILED notifier also runs on the hot plugged CPU.  This patch
converts the SMP functional calls into direct calls.

smp_function_call_single() executes the function with interrupts
disabled. This calling convention is not preserved because there
is no reason to do so.

Signed-off-by: Anna-Maria Gleixner <anna-maria@...utronix.de>
Acked-by: Paolo Bonzini <pbonzini@...hat.com>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Radim Krcmar <rkrcmar@...hat.com>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: kvm@...r.kernel.org
Cc: rt@...utronix.de
Link: http://lkml.kernel.org/r/20160713153335.452527104@linutronix.de
Signed-off-by: Ingo Molnar <mingo@...nel.org>
---
 arch/x86/kvm/x86.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 7da5dd2..6f90595 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -5662,15 +5662,13 @@ static struct notifier_block kvmclock_cpufreq_notifier_block = {
 static int kvmclock_cpu_notifier(struct notifier_block *nfb,
 					unsigned long action, void *hcpu)
 {
-	unsigned int cpu = (unsigned long)hcpu;
-
 	switch (action) {
 		case CPU_ONLINE:
 		case CPU_DOWN_FAILED:
-			smp_call_function_single(cpu, tsc_khz_changed, NULL, 1);
+			tsc_khz_changed(NULL);
 			break;
 		case CPU_DOWN_PREPARE:
-			smp_call_function_single(cpu, tsc_bad, NULL, 1);
+			tsc_bad(NULL);
 			break;
 	}
 	return NOTIFY_OK;